This past week both PSN and Xbox Live have been hacked,
PSN went down for maintenance again yesterday from 1pm to 8pm (PSN down twice in one week).
Hard drive upgrades is a factual eventuality on both PS4 and Xbox One.
Purchased games on PSN cannot be played during network maintenance.
Both PS4 & Xbox One require every disc based game to be installed.
More constant game updates on Xbox One & PS4 games than any Nintendo title.
Wii U has always supported external hard drives out of the box, although not needed any time soon because of no mandatory game installs.
Nintendo network although not as streamlined as PSN or Live works very smoothly with nearly no outages or maintenance hassles to interrupt gamers play sessions.
Ability to play games via game pad controller while others watch TV.
Lastly the most obvious reasons to choose Wii U over PS4 and Xbox One is all the Nintendo 1st party exclusives which can only be found on Nintendo systems are still the best exclusives overall.